This invention relates to conveyors. More particularly, this invention relates to the so-called harpoon-type conveyors suitable for transporting swarf-like materials.
A harpoon-type conveyor generally comprises one or more spaced, reciprocating drive members which usually comprise pairs of pushing blades, or harpoon plows, normally arranged in a V-shaped, or similar configuration. The harpoon plows are attached to a conveyor rod or chain, which may be and preferably is mounted on a suitable guide member situated in a conveyor trough. In any event, the harpoon plows are located in the trough and are adapted for reciprocating movement within the trough. Projecting members or barbs are secured to the inside surfaces of the conveyor trough and function to engage and retain the material being conveyed in the conveyor trough as the pushing blade or harpoon plow is shifted from a forward position to a rearward position during a return stroke. These conveyors are able to handle various types of swarf-like material, e.g., metal chips, from long and stringy to fine, with or without cutting fluids that may be present. Typical conveyors of this general type are illustrated in U.S. Pat. Nos. 3,112,025; 3,175,677; 3,158,257; 3,659,702; 3,799,329; 3,882,997; and 3,542,187; and German Pat. No. 1,139,068.
Though conveyors of this general type are generally well suited for transporting metal or plastic swarf, i.e., machining chips which are either relatively small and/or long and stringy, the conveyors experience problems when relatively large pieces of tramp material are mixed in with the swarf. These large pieces tend to wedge between the reciprocating harpoon plows and the barbs and cause jamming of the conveyor. In such instances, the conveyor must be stopped, and the larger pieces removed from the jammed conveyor. Jamming may also cause damage to the conveyor and/or the drive system therefor.